If there were an extra 3 or 4 seconds, or if you could pass through your duplicates, it would make this game significantly better. Spending an hour on a single puzzle, EVEN WITH THE GUIDE, is not fun. There is one puzzle in particular that has about a half-second timing window, if you miss it, you have to spend another 30 seconds to reset.

Playing with time is always confusing.You get more echo time to play with later in the game and eventually the Time Suit which allows you to pass through your time clones. It doesn't make the final puzzle any easier, though.

The time machine really breaks the flow of the game, in my opinion. The steps to properly use it are complicated compared to the gateways you get prior to it, and the signs and feedback when using it do very little to help explain things.

When I first got it, the tutorial popped up for it, and I attempted to perform the actions, but when doing so, the tutorial moved on to other steps, and I wasn't ready for it (and tutorials cannot be replayed, which is another problem altogether). It kept doing this, and I was left in the dark as to how this thing was supposed to work.

Later on, I tried solving a puzzle with it, and after several attempts, I thought I had the solution, but it didn't work. Annoyed, I used the the help system. Turns out, I did EXACTLY what the solution was, but for some reason that isn't clear to me. I think the issue was that I ran out of time (I agree with the OP, too little base time is given with this gateway), but the UI is not very useful. Why are there these bars that fill up, but have no text regarding what they're supposed to be filling up? What's the meaning of these two colors? Was this all explained in the tutorial that, for whatever reason, was too impatient for me? If so, and if the mechanics is gonna be this obtuse, why can't I just simply recall the tutorial in the menus to help out?

I'm not asking for the game to hold my hand, but if you're gonna make a multi-step, reality-warping, timing-based tool like this, clear feedback is needed for the player to understand how it works. It's the puzzles that are supposed to be hard, not the core mechanics.